Hi Guys

Quick Question:

Is Dextron 111 the stuff for Auto Trans/Power Steering in XJS 5.3 V12

 

OB,

Those boxes were originally designed to run on Dexron II. For most applications, Dexron III is a more advanced oil with no disadvantages to running in a Dexron II application. However, there are exceptions, where apparently the components can attack certain bearing surfaces! If you google the subject matter, you'll find plenty of viewpoints.

As "real" Dexron is a GM product anyway, I don't know, but I suspect that Dexron III is fully backwards compatible with your GM box. It's ok in my XJS 4.0 ZF box, anyway.

They key thing on changing auto fluid is the difficulty on changing as much of the old fluid which sits in oil lines, the cooler, the torque converter etc. If you just drain and fill the box you'll have done only 2.5 litres out of a total of 9 litres so you'll still have 67% dirty fluid in there! As you may remember, when I recently did my box, I did three drain and refills via the dipstick tube using my old supply of clean Dexron II. I then dropped the sump. changed the filter and refilled with Dexron III. I then did three more drains and refills with 10 mile trips in-between. That was the only way that I felt comfortable that I'd eventually changed most of the old fluid.

Hope that helps a little

Paul

 

You can flush iot but you need an awful lot of ATF which will be wasted...

Open the return line and feed line of the ATF cooler. Place the return line in a fresh barrel/canister of ATF. Place the feed line to the cooler into a canister to catch the old ATF.

Start the engine and let it run. Whilst standing up the RPM a little. Then whilst standing with the brakes fully applied, switch through all the gear selector positions (even 2 and 1) and hold it for a couple of seconds.

keep an eye on the colour of the ATF coming out of the feed hose. Once it is red (as ATF should be) it is all flushed and new.

You have to estimate twice the amount of fluid you need for a flush. That means about 10l for the flush and about 10l for the fill.

When flushed, top up through the dip stick.

Be careful though, not all trannys like a flush and many ONLY want a change of that what is in the sump. The 5hp24 in my XJ8 does NOT like flushes and will most commonly quit working after it. It actually NEEDS debris and grime in the ATF to fill up tolerances in the old tranny. If it was brand new (I mean really brand new!) then a flush is no worry. But an aged tranny CAN go kaput when flushed... Just as a word of warning. Not because of the process but because the materials used to fill tolerances which have been removed allow for the new fluid to for example bypass a pressure regulation valve (typical death of the XJ8 tranny).

 

Hi Paul@Daim

Wow! lots of food for thought there Guys

but I only bought 5L as a Top Up from when I changed the Rad and to Top Up the Power Steering.

So thanks for the heads up on that.

 

I'm with Daim. Flushing most transmissions just is not necessary. A waste of oil and/or money.


His power flush can and does work as to getting the most o the of out and the new in. But, caveat, don't let it go "dry". The clutch material can go fast...


And for old ones. More likely than not, a flush will finish it off. Not good, at all.


Carl

 

Hi Carl

I've heard some 'Horror Stories' if I decide to do it, I'll be Careful!

 

OB,

Part of the reason that I did multiple drains and fills (apart from the difficulty is disconnecting the return oil cooler pipe at the box!) was to achieve a more gradual dilution and replenishment and hopefully avoid any flushing residue problems.

Having done a total of seven drains and refills, I used a total of 18 litres of fluid, although that included 7.5 litres of NOS Dexron II that I had in the garage. With a total of 7 drains and refills, I (think I?) still theoretically have .85 litres of "dirty" fluid left in the transmission carrying that "necessary" debris and grime around!

Paul

 

Hi Paul

That Stuff is quite expensive, I will keep you all posted if I get around to doing mine.

 

I normally buy cheap ATF. I have a brand here called "Mannol". They are cheap and VERY cheerful! My XJ8 runs on their ZF approved fluid, my power steering has their Dexron III in it. My XJ-S will get their ATF Dexron II...

I paid I think like €2,99/l which is like a bargain but it is their normal price!

 

That's interesting Daim but as this is for a Top Up, I would feel much happier using a well known make,

 

Installing a drain plug in the transmission pan really simplifies things.

My XJR had a drain plug. Early on I replaced the filter and cleaned the pan. After that...for the next 140k miles that I used the car....I'd drain the pan every-other-time I changed engine oil. It took about 4 quarts to refill. Anyhow, the ATF was constantly being 'freshened up'. Added maybe 10 minutes to a routine service. Probably overkill but it was so easy that there was no compelling reason not to do it.

I added a drain plug to the TH400 of my Series III and plan to do the same thing.

Cheers
DD

 

Hi Doug

Any chance of a bit of a Write up on how you did the plug, that would be interesting to lots of people on here.

 

Mannol is actually a very old and well known brand for classic oils and budget stuff. Kind of like Castrol, just oooooooolder

 

Hi Daim

Not one I've heard of in the UK so I will be sticking with Dextron.

 

OB,

Comma's Dexron III equivalent is only about £20 per 5litre, so even a multi-fill routine is only about £50.

Doug's suggestion is exactly what I'm going to do now - suck out and replace the 2.5 litre in the sump every year. Then the box will have reasonable fluid all the time. If there's no plug on the GM box, you can still use a compressor-driven or even hand-vacuum extractor and do the same job. Apart from when I changed the filter, all my drain and refills were done via the dipstick.

Paul

 

Faster and easier than waiting for me to write something up.......



There are other methods. A bit of You Tubing should reveal them quickly

Cheers
DD

 

Alex,

If I were you the first time I would drop the transmission sump to drain the oil. There is a magnet in the pan that collects metal debris, when I pulled the pan off my TH400 this magnet was chocka full of filings as was the bottom of the pan, oil looked clean on the dipstick. You can also change the filter while you're at it.

Once you have done this, then subsequent changes can be done via a drain plug.

 

Hi Paul@Doug@Warrjon

Many Thanks for your help Guys, quite a lot to consider there but I may try the Suction method first.

 

I would drop the pan and change the filter.

I know the guy in our local hardware who is a transmission mechanic by trade, he was telling me horror stories of guys who swapped out a bad transmission with a good 2nd hand one, only to have the new transmission fail soon after. They swapped the trans without flushing the external lines and cooler. The debris clogs the filter staves the trans of oil and burns the clutches.

For a few extra $ and a bit of extra time it's worth it for the peace of mind.

 

Cheers Warrjon

I will add it to my list of Winter Projects but the Car has only done 25,000 Miles, so maybe it doesn't need doing just yet (but how would I know)